Question

If sin 2A= cos 4A then the measure of angle A is
(A) 15°
(B) 20°
(C) 25°
(D) 30°​

Answer 1

Answer:

sin 2A = cos 4A

Let us change sin 2A in cos value-

Cos(90 - 2A) = cos 4A

90 - 2A = 4A

90 = 4A + 2A

90 = 6A

A = 90/6

A = 15

So, the correct answer is (A) 15°

Answer 2

Answer:

Step-by-step explanation:Given that,

Sin2A=Cos4A

Sin2A=Sin(90°-4A)

2A= 90-4A (eliminate sin both side)

2A+4A=90

6A=90

A=15